Xiong, K and Asher, SA
(2012)
Impact of ion binding on poly-l-lysine (un)folding energy landscape and kinetics.
Journal of Physical Chemistry B, 116 (24).
7102 - 7112.
ISSN 1520-6106
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Abstract
We utilize T-jump UV resonance Raman spectroscopy (UVRR) to study the impact of ion binding on the equilibrium energy landscape and on (un)folding kinetics of poly-l-lysine (PLL). We observe that the relaxation rates of the folded conformations (including π-helix (bulge), pure α-helix, and turns) of PLL are slower than those of short alanine-based peptides. The PLL pure α-helix folding time is similar to that of short alanine-based peptides. We for the first time have directly observed that turn conformations are α-helix and π-helix (bulge) unfolding intermediates. ClO 4- binding to the Lys side chain -NH3+ groups and the peptide backbone slows the α-helix unfolding rate compared to that in pure water, but little impacts the folding rate, resulting in an increased α-helix stability. ClO4- binding significantly increases the PLL unfolding activation barrier but little impacts the folding barrier. Thus, the PLL folding coordinate(s) differs from the unfolding coordinate(s). The-π helix (bulge) unfolding and folding coordinates do not directly go through the α-helix energy well. Our results clearly demonstrate that PLL (un)folding is not a two-state process. © 2012 American Chemical Society.
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Details
Item Type: |
Article
|
Status: |
Published |
Creators/Authors: |
|
Date: |
21 June 2012 |
Date Type: |
Publication |
Journal or Publication Title: |
Journal of Physical Chemistry B |
Volume: |
116 |
Number: |
24 |
Page Range: |
7102 - 7112 |
DOI or Unique Handle: |
10.1021/jp302007g |
Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
Refereed: |
Yes |
ISSN: |
1520-6106 |
MeSH Headings: |
Ions--chemistry; Kinetics; Perchloric Acid--chemistry; Polylysine--chemistry; Polylysine--metabolism; Protein Folding; Protein Structure, Secondary; Sodium Compounds--chemistry; Spectrum Analysis, Raman; Water--chemistry |
Other ID: |
NLM NIHMS380037, NLM PMC3381074 |
PubMed Central ID: |
PMC3381074 |
PubMed ID: |
22612556 |
Date Deposited: |
08 Feb 2013 20:47 |
Last Modified: |
12 Jun 2021 23:55 |
URI: |
http://d-scholarship-dev.library.pitt.edu/id/eprint/17280 |
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